Ultra-Thin Membrane Fabrication Technology Development for Gas Separation

In general, for a membrane separation system in a given process scheme and operating conditions, gas permeance (pressure normalized flux) controls the required membrane surface area to achieve desired separation level and hence membrane system and operating costs. Therefore, high permeance membrane systems are typically required for techno-economically viable gas separation at industrially dictated process scales. Gas permeance through a membrane is dictated by the permeability and thickness of the selective layer. While numerous R&D efforts have led to development of novel materials with high permselectivity, many of these materials never leave the bench-top and very few make progress towards commercialization often due to the difficulties associated with transforming these interesting materials chemistries into membranes with robust, thin (ca. 100 to 500 nm) selective layers on commercially attractive support platforms.  Our efforts have been focused on development of a commercially viable coating technology to fabricate composite membranes with high permeance by minimizing the selective layer thickness. Using an ultrasonic atomization-based deposition process, we have developed methods to fabricate ultra-thin (ca. 100nm) thick defect-free membrane selective layers on commercially attractive porous polymeric supports for ultimate deployment as spiral wound modules.  In this presentation, we will present our work on fabrication of ultra-thin CO₂ selective membranes comprised of model materials with permeance 1 to 2 orders of magnitude higher than previously reported for those materials. Furthermore, application of these methods to fabricate ultra-thin composite membranes with unprecedented CO₂ permeances on the order of 5-10K GPU will be discussed.